1. Field of the Invention
The present invention relates to an insert for a cylinder sleeve or a cylinder of an internal combustion engine, for narrowing the diameter of the cylinder sleeve in the region of the top land at the upper dead center of a piston guided in the cylinder sleeve. Such an insert serves to strip off carbon that accumulates on the top land, and prevents contact of the carbon with the working surfaces of the cylinder sleeve or the cylinder.
2. The Prior Art
An insert of this type is described in U.S. Pat. No. 3,489,130. This reference describes a piston/cylinder arrangement for internal combustion engines, to which a ring-shaped insert is assigned in order to form a narrowed segment of the inside wall of the cylinder.
A combined device consisting of a sealing element towards the cylinder head and carbon stripper is described in U.S. Pat. No. 4,474,147. For this purpose, the closed ring insert is structured angled away towards the cylinder head.
A similar insert is described in German Patent No. DE 35 43 668 A1. In this case, the insert, formed as a deep-drawn part or lathed part, is held by means of a radial collar, which is pressed against the cylinder crankcase by the cylinder head.
Another insert is described in German Patent No. DE 103 21 034 B3. This reference describes a reciprocating piston internal combustion engine having a cylinder head and a cylinder crankcase with a sleeve to which a ring-shaped insert is assigned. The insert projects beyond the sleeve on its cylinder-head-side end, and is fitted between the sleeve and the cylinder head, preferably without play. After assembly of the cylinder head, the insert is subject to pressure stress, and thereby held in the sleeve.
A similar insert is described in DE 35 43 668 A1. In this case, the insert, formed as a deep-drawn part or lathed part, is held by a radial collar that is pressed against the cylinder crankcase by the cylinder head. Such inserts are difficult to produce and fit into the sleeve, because of the close tolerances in production and assembly, and therefore are not optimally suited for series production.
Additional inserts are described in German Patent No. DE 103 21 034 B3 and DE 198 11780 C1.
All of the inserts described in the references cited above have in common that they are always formed from closed rings.